Answer: y = (-1/2)x + 2
Step-by-step explanation:
Answer:
B
Let total number of students be x.
Ratio of boys to girls= 5:7
=5x:7x
According to question,
5x =95
Or x=95/5
x=19
Now,
Number of girls =7x
=7*19
=133
Your first point should always be shown in the y-intercept following the standard form for slope-intercept form
Y = mx + b
b = y - intercept
In this case your first point would be (0,1)
You next point would be following the slope which is -2x. When you graph a equation always know that it is rise over run. For this line, it would be going from left to right since it is a negative line.
Your second point would go down 2 points from your starting point (0,1) and run 1 to the right in the x-axis, which is also called, (1,-3)
As soon as I read this, the words "law of cosines" popped
into my head. I don't have a good intuitive feeling for the
law of cosines, but I went and looked it up (you probably
could have done that), and I found that it's exactly what
you need for this problem.
The "law of cosines" relates the lengths of the sides of any
triangle to the cosine of one of its angles ... just what we need,
since we know all the sides, and we want to find one of the angles.
To find angle-B, the law of cosines says
b² = a² + c² - 2 a c cosine(B)
B = angle-B
b = the side opposite angle-B = 1.4
a, c = the other 2 sides = 1 and 1.9
(1.4)² = (1)² + (1.9)² - (2 x 1 x 1.9) cos(B)
1.96 = (1) + (3.61) - (3.8) cos(B)
Add 3.8 cos(B) from each side:
1.96 + 3.8 cos(B) = 4.61
Subtract 1.96 from each side:
3.8 cos(B) = 2.65
Divide each side by 3.8 :
cos(B) = 0.69737 (rounded)
Whipping out the
trusty calculator:
B = the angle whose cosine is 0.69737
= 45.784° .
Now, for the first time, I'll take a deep breath, then hold it
while I look back at the question and see whether this is
anywhere near one of the choices ...
By gosh ! Choice 'B' is 45.8° ! yay !
I'll bet that's it !
